Alexander beckers



UNITED STATES PATENT @rrrch ALEXANDER BEOKERS, OF NEW YORK, N. Y.

IMPROVEMENT IN STEREOSCOPES.

Specification forming part of Letters Patent No. 188,763, dated March27, 1877; application filed February 8, 1877.

To all whom it may concern:

Be it known that I, ALEXANDER BEcKERs,

' of the city and State of New York, have invented an Improvement inStereoscope 1nstruments, of which the following is a specification hoodis less than that of the picture and so proportioned that the visiblesurface of the picture or of the border around the same is not changedby adjusting the picture; and I provide a peculiar picture-holder, andvary the position of the same relatively to the hood, so as to suitpictures of difi'erent sizes, or to show more or less of the borderaround the pictures a By this construction I obtain the stereoscopiceffect of the entire picture, and do not cover up any part of eitherpicture.

In the drawing, Figure 1 is a vertical longitudinal section of theinstrument. Fig. 2 is a plan of the same sectionally,-at the line a: m;and Fig. 3 is an elevation of the lensholder and hood.

The lenses a a are of usual character, set in the shield or lens-holderb, that is provided with a'base, c, to which the handle at is connectedby swinging bracket-jaw 0. This jaw e is made of a metal plate fastenedacross the end of the handle and having bracket-shaped end piecesextending upwardly and backwardly at each side of the base 0 andconnected thereto. by the screws 2. This forms a firm connection andsupport, by which the stereoscope instrument is held when in use; andwhen the parts are closed for packing or transportation, the handle isswung up behind the lens-holder 12, into the position shown by dottedlines, thus occupying but little space, and it is unnecessary to detachthe handle, as

heretofore,

The hood f is made to surround the lenses, as in the ordinary manner,except that it is carried beneath the glasses and turned upwardly, asshown at 3 3, to leave an opening for the persons nose when placing theinstrument close up to the face. This character of shield not only shutsoff rays of light from below the eyes, but aids in bringing the instrument to the proper central position before the face.

There are side pieces g, Lop piece h, and bottom piece It, forming anopen box around the lens-holder extending forward; and there is asliding shield or septum outside the parts 9 h, the same being formed ofthe sides 1 1, top m, and bottom a, but the bottom a is above thestationary bottom k, and it slides beneath the lower edges of the sidepieces 9 in a slot provided for it, and there are guideplates 0 beneaththe edges of k.

A central division, 0, extends from the top m to the bottom a, and it isof a proper width to prevent the rays from the right picture enteringthe left lens, and vice versa.

The lever s is pivoted at 6 to a link, .9 that is attached at 7 to thecentral division 8 of the lens-holder, and a second link, t, connectsthe sliding shield or septum to the lever s, and the lower end of thislever s is pivoted at 9 to the slide a, that carries the picture, sothat as the picture is moved forward the shield or septum is moved bythe lever in the same direction and a proportionately less distance.There is a slot through the base 0 for the lever s to move in, and thepin 12 upon the lower edge of the septum is guided in said slot andkeeps the septum in its proper position while being moved.

The slide a is in the ways a that are attached to the base 0, andgrooved on their faces to receive the slide u, and the end of this slidea is slotted to receive the cross-bar c and clamping-screw c,- and thereis a post or finger, to, standing up behind the picture to support thesame, and a spring, 10, to clamp the picture 11 to'the finger w.

This construction insures the proper position of the stereoscopepicturesregardless of their size, or of the size of the card upon which they areaffixed, because the spring 10 indicates the point at which the centerbetween the two pictures is to be placed; and the cross-bar 'U is areliable support for the pictures, but does not require to be long andcumbersome, as those now in use.

It is preferable to make the spring 10 of a wire, that runs horizontallyalong in the picture-holder 2;, so that the vertical part 10 acts bytorsion upon the horizontal part of the spring-wire. This increases thelength of the spring and retains the vertical portion in place.

It will now be understood that the picture and holder are to be adjustedforward or back in the slot or until the observer can see the border ofthe picture at the middle, as illustrated by the dotted lines 15, so asto take in the whole picture. The picture-holder and its slide can thenbe moved back and forth until the proper focus is obtained, and in sodoing the entire picture remains in view, because the central partitionmoves with the picture a proportionate distance to always shut off therays of light from the second picture, so that only the one oppositeeach lens will be visible, and at the same time the vertical angles 16of the hood will intercept the rays of light, so as to confine thevision to the picture, and to a border around the picture of greater orless width, according to the relative position of the picture to theforward edges of the hood and the lenses.

1 claim as my invention- 1. The movable hood with the vertical sep' tum0, in combination with the lever 8, picture-slide, picture-holder, andstereoscopic lenses, substantially as set forth.

2. The hood made as a box-that is, around the lens-holder and itsbox-and adjustable in its position to the lens-holder, substantially asset forth.

3. The movable picture-holder, adjustable upon the picture-holdingslide, in combination with the movable hood, the mechanism for movingthe hood, and the lens and bolder, substantially as set forth.

4. The sliding picture-holder, made of the cross-bar '2), central spring10, and post or finger w, substantially as and for the purposes setforth.

5. The handle (I and bracket-yoke a, combined with the base 0 andlens-holder b, substantially as set forth.

6. The hood f, made with the central portions 3 turned upwardly andforming a guide, in combination with the lens-holder b, substantially asset forth.

Signed by me this 6th day of February, A.

ALEX. BECKERS. Witnesses:

GEo. T. PINOKNEY, CHAS. E. SMITH.

